Insecticide



- Patented Nov. 28, 1944 UNITED msac'rrcma Seaver A Ballard, Oakland, and Vernon E. Ham-y. El Cerrito, Calif., aslignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing.

7 Claims.

This'invention deals witha new insecticidal composition of great utility and is particularly concerned with toxic substances suitable for use therefore expensive and not always obtainable in the desired quantities.

11; is the object of the present invention to ro vide an insecticide which can be readily manufac- 1 tui'ed from readily available domestic, inexpensive materials. It is a further object of this injvention to provide a very toxic, moderately fastacting insecticide which is little, if atal-l, toxic to man'and other warm-blooded "animals. Another obiectis to provide a synthetic toxicant which is stable toward sunlight and which is compatible with plant toxics. Other and further objects will be apparent from reading the-speciflcation. l a It has been found that certain ketol esters may be utilized as insecticides to accomplish one or more of the foregoing objects.

Theketols, to be esterifled, as will be discussed later, to produce the ketol esters of the invention, ,are members of agroup of carbocyclic unsaturated'ketols having the carbonyl group in the ring and having from 8 to 24, or even more e. g, 34,

carbonatoms. Ketols of the above group having at least .15 carbon atoms are preferred, it having i been found that the higher members 'of the esterifled series'have a more pronounced insecticidal activity.

Suitable unsaturated carbocyclic ketols yielding particularly potent esters may be produced by the aldol condensation of lower alicarbocyclic ketones such as cyclopentenone, cyclohexenone,

cycloheptenone, isophorone, and the like. In gen eral cyclic ketones applicable for the purpose of preparing suitable ketols .are those having from about 5 to 12 carbon atoms. I

A class of cyclic ketones suitable for preparing the ketol esters via the ketols, e. g. isophorone may be prepared by condensing simple. aliphatic ketones such as acetone and methyl ethyl ketone.

The condensation reactions referred to inthe foregoing may be carried out with the aid of 1 caustic alkali catalysts more basic than lime, e, g., the alkali metal hydroxides such as sodium and potassium hydroxides, sodamide, sodium ethylate,

or other alkali metal alkylates.

,The ketols produced by condensing lower ketones ordinarily consist of a mixture of dimers, trimers and other polymers having one or several Application December 1, 1941, Serial No. 421,246

carbocyclic rings, and ordinarily. at least meet the rings is unsaturated. If desired, the mixture of carbocycli'c ketols so produced can be used as is, for the purpose of preparing the esters of the 1 present, invention, or else.it can first be fractionatedto separate fractionshaving different boiling ranges and the several fractions then esterifled. Such fractionation is often desirable in that the esters prepared from different fractions-may .vary in their toxicity, and accordingly in the use to which they are best adapted. Thus the higher boiling fractions yield esters which are moretoxic but less volatile than equivalent esters obtained ..with lower boiling fractions. I Therefore the former are very suitable for use in plant or cattle sprays, while thelatter are more suitable for use where volatility'is of importance, e. g., in household sprays.

The acids suitable for esterifying the ketols are carboxylic acids of from 1-10 and preferably from 2-5 carbon atoms. These acids may be aliphatic, e. g., lower fatty acids such asacetic, propionic, butyric, valeric, etc.; alicyclic, e. g. lower naphthenic acids such as cyclo-butyl carboxylic acids, cyclo pentyl carboxylic acids, lower petroleum naphthenic acids, etc.; aromatic acids, e. g., benzoic, toluic acids, etc.; or heterocyclic such as pyridine carboxylic acids, although the aliphatic acids are preferred.

In general, the usual method of esteriflcation, such as reacting the hydroxy compound to be esterifled with an acid, acid chloride, :acid anhypart of 60% NaOH solution.

dride or ketone of the corresponding number of carbon atoms is operative, to produce the instant ketol esters. Some of the ketols, however, maybe rather dlfflcult to esterify, and in such instances th acid chloride or acid anhydride method of esterification will be found preferable. Following is an illustrative example of producing and testing an especially suitable ketol ester:

Isophorone was condensed to form di-isophorone by means of NaOH. A vessel equipped with heating and stirring means was charged with four parts by weightoi isophoronc and about one V The phases were separated and the upper phase was washed with water to remove entrained NaOH solution. The organic material then consisted of a mixtureof unreacted isophorone and its condensed dimer,

and possibly some trimer. The-unreacted mate- 'rial was first removed overhead by distillation under a vacuum of about 2 mm., and then the di-isophorone was taken of! overhead, whereupon it solidified to form a crystalline solid having a melting point of about 84 9. Two moles of this product, which was. identified as di-isophorone, were then refluxed with 3 moles of acetic anhydride for 8 hours at about 180 C. The acetic acid was removed as formed and a conversion of 96.5% of the di-isophorone to the acetate was obtained. 5 i

ModifiedPeet-Gradytests were made of this ketol ester. The general test is fully described in the 1940 Blue Book," published by the publisher asoaoae oils, soaps, and the like may be used in combinaof Soap and Sanitary Chemicals, shown on pages 193-197 as the large group method. Briefly,

the test as practiced consists of releasing 100-150 flies in an air-conditioned cage 6' x6 x 6' and spraying them with 6 moles of insecticide. After ten minutes exposure, the number of flies which are incapacitated or knocked down is noted and all the files are transferred to a cage and allowed to recuperate in fresh air for 24 hours, when the dead files are counted. For the purpose of this study, the oficial Peet-Grady study was not fol-' lowed in calculating the results, but only the percentages knocked down at 10 minutes and killed at 24 hours were recorded. For the'purpose of the comparison, a spray was included in this test comprised 7.3% of pyrethrum extract and 92.7%

of odorless base (kerosene) as a standard, and

which had a rating of AA according to the standards of the National Association of Insecticide and Disinfectant Manufacturers Association. In the tion with such sprays. In the same manner the ketol esters themselves without the addition of oil secticides.

Theesters of ourinvention may also be adgroup in the cyclic ring, said compound being furtable below, a comparison is made of the standard '30 and an insecticidal composition containing the ketol esters'of the present invention:

Per cent of Per cent of .standard standard knock- 24-hour down kill 7.3% by .volume pyrethrum extract,

20-1 concentrate, and 92.7% by volume of odorless base (kerosene) 100 100 4% p rethrum extract by volume and 2.4% of dl-isophorone acetate (a kevol ester) and 93.6% odorless base (kero:ene).. 99 110 A few drops of a solution of the above ketol Solved in a light hydrocarbon oil such as kerosene or kerosene distillate with or without the addition ther characterizedby having between 10 and 34 carbon atoms.

2. An insecticidal composition comprising a carrier and a carboxylic acid ester of an unsaturated alicarbocyclic ketol having the. carbonyl group in the cyclic ring, said compound being further characterized by having 20 carbon atoms.

3. An insecticide comprising a carrier and diisophorone acetate.

4. An insecticidal composition comprising a carrier and a carboxylic acid ester of an unsaturated ketol having at least 2' alicarbocyclic rings.

5. A household insecticide comprising an insecticidal hydrocarbon spray oil and a carboxylic acid ester of a cyclic unsaturated ketol having the carbonyl group in the ring, said compound being further characterized by having between 10 and -34 carbon atoms. 

